It has been proposed in the past to design a vehicle so that when the accelerator pedal is excessively stepped on or depressed so as to result in wheel slippage, brake fluid is sucked or drawn from a reservoir through a fluid passage or a communicating hole within the master cylinder in accordance with a brake pressure control such as a TRC control (a traction control). In this way the wheel cylinder pressure in the wheel is controlled. For this reason, a pump provided in the output port end of the master cylinder is driven so that the brake fluid is drawn from the reservoir and is guided to the wheel cylinder. However, in situations where a lot of brake fluid is supplied to the wheel cylinder at a time of starting the traction control, the flow passage for the brake fluid forms a resistance with respect to the amount of discharge of the pump and so it is difficult to draw out the required amount of fluid. There thus arises the possibility that an insufficient amount of brake pressure will be supplied to the wheel cylinder.
In an attempt to address this problem, it has been proposed, for example in EP 550710, to provide a bypass passage in a portion joining a reservoir connecting port of the master cylinder to a pressure generating chamber within the master cylinder and a check valve, with the check valve being located in the middle of the bypass passage for permitting flow from the reservoir to the pressure generating chamber while preventing flow in the opposite direction. This is illustrated in FIG. 5.
However, in this system in which the bypass passage is provided within the master cylinder for feeding a sufficient amount of brake fluid to the wheel cylinder and the check valve is provided in the middle of the bypass passage, the space required for arranging the bypass passage and the check valve within the master cylinder is somewhat problematic.
A need thus exists for a master cylinder which addresses the foregoing drawbacks and disadvantages.
It would be desirable to provide a master cylinder for drawing brake fluid from a reservoir through a pressure generating chamber of the master cylinder at a time of controlling fluid pressure to supply brake pressure to the wheel cylinder of a wheel, wherein the check valve is easily arranged while at the same time ensuring that sufficient suction can be secured from the master cylinder.